Preparation of long-circulating dihydromyricetinliposomes and its pharmacokinetics in rats / 中草药

Objective To prepare dihydromyricetin (DMY) long-circulating liposomes and evaluate in vitro release dynamics and in vivo pharmacokinetics in rats. Methods Film-ultrasonic method was used to prepare DMY liposomes by single factor experiment and orthogonal test to optimize the formulation and preparation of DMY liposomes. The particle size and zeta potential of liposomes were determined by laser particle size analyzer. The morphological examination of liposomes was performed by using transmission electron microscopy. The liposome release in vitro was studied using dialysis method. DMY concentration in rat plasma was determined by the established LC-MS/MS method. Results The optimal prescription was 75∶20∶5 for soybean phospholipid-cholesterol-mPEG 2000-DSPE, and 1∶12 for DMY-lipid (wt/wt) with the ultrasonic time of 20 min and loading temperature of 60 ℃ in pH 5.0 PBS buffer. Under the optimized conditions, DMY liposomes was sphere with mean particle size of (117.9 ± 5.5) nm and mean zeta potential of (−2.6 ± 1.7) mV, the encapsulation efficiency and drug-loading content was (54.7 ± 3.3) % and (4.3 ± 0.2) %, respectively. The in vitro accumulative release rate of 48 h was 86% in pH 1.2 and pH 6.8 dissolve medium. Compared with free DMY, the t1/2z and AUC0-∞ of DMY liposome were increased by 2.7-fold and 1.8-fold, respectively. Conclusion Compared with free DMY, DMY liposomes released gently and slowly in vitro, eliminated slowly in vivo, and had higher bioavailability of oral administration.

Preparation and pharmacokinetics of honokiol long-circulating liposomes / 中草药

Objective To optimize the preparation process of honokiol long-circulating liposomes (HLCL) and study the in vitro and in vivo release. Methods An orthogonal experiment was designed to optimize the composition of HLCL using entrapment efficiency as evaluation indicator. The liposome surface morphology was observed by transmission electron microscope (TEM), and the liposome release in vitro was studied by dialysis method. The concentration of honokiol in rat plasma was determined by the established LC-MS/MS method, and the differences in pharmacokinetic parameters were compared after honokiol and HLCL (20 mg/kg) were orally administered to SD male rats, respectively. Results The optimal composition of HLCL was 8:1:1 for soya phosphatidyl choline-cholesterol-mPEG2000-DSPE, and 1:10 for honokiol-liposome materials with the ultrasonic time of 12 min. Under the optimized conditions, HLCL was sphere with mean particle size of 121.5 nm and mean Zeta potential of -30.8 mV, the encapsulation efficiency and drug-loading content was 84.7% and 10.4%, respectively. In vitro release results showed that the liposomes could be gently and slowly release with the 24 h cumulative release rate at pH 1.2 and pH 6.9 dissolve medium of 80% and 71%, respectively. Based on the pharmacokinetic results, Cmax, tmax, and t1/2 were (23.29 ± 11.76) ng/mL, (0.13 ± 0.05) h and (10.59 ± 5.72) h for HLCL, and (79.34 ± 56.32) ng/mL, (0.30 ± 0.07) h and (4.44 ± 3.14) h for honokiol, respectively. There was no significant difference about the AUC0-∞ following oral administration of honokiol and HLCL at isodose honokiol (20 mg/kg). Conclusion Compared with honokiol, HLCL was released gently and slowly in vitro, absorpted rapidly and eliminated slowly in vivo.

Preparation of paraoxonase liposomes and their pharmacokinetics in rats / 中华危重病急救医学

Objective To prepare paraoxonase 1 (PON1) liposomes, and investigate pharmacokinetics of common PON1 liposomes (L-PON1) and polyethylene glycol-modified PON1 long circulating liposomes (PEG-PON1-LCL) in rats after intravenous administration. Methods L-PON1 and PEG-PON1-LCL were prepared by film dispersion method. The entrapment efficiency, mean diameter and Zeta potential of the liposomes were measured, and the stability was evaluated. Thirty-six Wistar rats were divided into three groups according to random number table, with 12 rats in each group. The rats were intravenously administrated with PON1, L-PON1 or PEG-PON1-LCL 700 U/kg, respectively. The activity of PON1 in serum was determined by phenyl acetate method, the activity of PON1 at different time points after drug administration was compared with that before drug administration, and the difference value was considered as the activity of exogenous PON1, and PON1 activity-time curve was plotted. The pharmacokinetic parameters were calculated and analyzed by DAS 2.0 pharmacokinetic program and SPSS 17.0. Results The entrapment efficiencies of L-PON1 and PEG-PON1-LCL were above 85%, the mean diameter was about 126 nm, and Zeta potential was -14.35 mV. After 2 weeks of preservation, the above parameters showed no obvious change, indicating that liposomes had good stability and the properties of preparations were basically stable. Compared with purified PON1 administration, after L-PON1 and PEG-PON1-LCL administration, the activity of PON1 was increased, the half-life of PON1 activity in rats was significantly prolonged [the half-life of distribution (T1/2α, hours): 0.142±0.018, 0.147±0.021 vs. 0.126±0.022; the half-life of clearance (T1/2β, hours): 3.877±1.010, 4.520±1.117 vs. 1.226±0.422], the area under PON1 activity-time curve (AUC) was significantly increased [AUC from 0 hour to 24 hours (AUC0-24, U·h-1·L-1): 499.305±64.710, 563.576±70.450 vs. 18.053±2.190; AUC from the immediate injection to the disappearance of PON1 activity (AUC0-∞, U·h-1·L-1): 516.256±60.940, 587.801±76.210 vs. 21.044±3.250], the apparent volume of distribution (Vd) and clearance (CL) were significantly decreased [Vd (L): 0.140±0.065, 0.144±0.064 vs. 0.493±0.032, CL (L/h):0.039±0.008, 0.034±0.006 vs. 0.952±0.082, all P < 0.05]. There was no significant difference in pharmacokinetics between L-PON1 and PEG-PON1-LCL. Conclusions The film dispersion method prepared PON1 liposomes have high entrapment efficiency and small particle size with a good stability. Both liposomes can raise PON1 activity in vivo, change the pharmacokinetics of PON1 in vivo, prolong the resident time of PON1 in the blood circulating system, and compensate for the short half-life of PON1 in vivo.

Nanoformulations of the vascular inhibitors: Combretastatin A4 and combretastatin A4 phosphate / 国际药学研究杂志

Combretastatin A4 (CA4), a vascular inhibitor, can target tubulin and inhibit tubulin polymerization, thus it can inhibit the tumor blood vessels and has antitumor effect. But it is insoluble in water and has low bioavailability. CA4 phosphate (CA4P), the derivative of CA4, can improve the solubility of CA4 and convert into CA4. CA4P is undergoing phase II/III clinical trials abroad. However, CA4P has several undesirable side effects and relative short half-life in vivo. Nanoformulations can increase the dissolution and absorption of the drug and obtain controlled release and targeting, prolong the efficacy and reduce side effects. Working on the physical and chemical characteristics and biological pharmacy defects of CA4 and CA4P nanoformulations may change the dissolution, absorption and distribution of the drug. This paper reviews the current nanoformulations of CA4 and CA4P, including den-drimer, polymeric micelle (PM), nanoparticles (NP), long-circulating liposome (LCL), and discusses the prospects of their nanoformulations.

Preparation and pharmacokinetics of gambogic acid long-circulating liposomes / 中草药

Objective: To optimize the preparation process of gambogic acid (GA) liposomes and study the in vitro and in vivo release. Methods: The detection method of GA was established, using the Box-Behnken experiment design to optimize liposomes formula, GA liposomes were obtained with the highest encapsulation efficiency; Using scanning electron micrographs (SEM) to observe liposome surface morphology, using the dialysis method to study the liposome release in vitro, we also measured the stability of liposome in 15 d; Male Wistar rats were injected with GA or GA liposomes (1 mg/mL) via tail vein, UPLC-MS/MS method was used to determine the drug concentration, and differences in pharmacokinetic parameters of the two drugs were compared. Results: After Box-Behnken optimization, the encapsulation efficiency of liposomes was 92.3%, and the optimized liposomes formula is cholesterol of 440 mg, egg phosphatidylcholine of 1823 mg,,and istearoyl phosphoethanolamine-PEG 2000 of 705 mg, liposomes had uniform particle size and smooth surface; In vitro release results showed that the liposomes could be gentle and slowly release and had a long- term effect. The liposomes were stable keeping in 4 ℃ within 15 d; In in vivo study, the half-life of GA liposome was 9.97 h, 4.43 times of GA; AUC0-24 h of GA liposome was 22.55 μg∙h/mL, 4.73 times of GA. Conclusion: Compared with GA, GA liposome has the characteristics of long-circulating, high blood drug concentration, and could release smoothly.

Nanoformulations of the vascular inhibitors:combretastatin A4 and combretastatin A4 phosphate / 国际药学研究杂志

Combretastatin A4(CA4),a vascular inhibitor,can target tubulin and inhibit tubulin polymerization,thus it can inhibit the tumor blood vessels and has antitumor effect. But it is insoluble in water and has low bioavailability. CA 4 phosphate (CA4P),the derivative of CA4,can improve the solubility of CA4 and convert into CA4. CA4P is undergoing phaseⅡ/Ⅲclinical tri?als abroad. However,CA4P has several undesirable side effects and relative short half-life in vivo. Nanoformulations can increase the dissolution and absorption of the drug and obtain controlled release and targeting,prolong the efficacy and reduce side effects. Work?ing on the physical and chemical characteristics and biological pharmacy defects of CA4 and CA4P,nanoformulations may change the dissolution,absorption and distribution of the drug. This paper reviews the current nanoformulations of CA4 and CA4P,including den?drimer,polymeric micelle(PM),nanoparticles(NP),long-circulating liposome(LCL),and discusses the prospects of their nanofor?mulations.

Preparation and Evaluation of Long-circulating Liposomes of Paraoxonase / 中国医科大学学报

Objective To prepare the long-circulating liposomes of paraoxonase(PON).Methods The long-circulating liposomes of paraoxonase were prepared by film dispersion method.The encapsulation efficiency was determined by gel column.The effects of the factors on the encapsulation efficiency,such as the weight ratio of paraoxonase to phospholipid,cholesterol(Choi) to phospholipid,PEG-cholesterol (PEG-Chol) and the iron strength of water phase,were investigated respectively.Then the formulation was optimized by orthogonal design.Results The encapsulation efficiency of the paraoxonase liposomes was 87.66±3.46%,and the average diameter of the liposomes was about 126 nm.There was no significant change on encapsulation efficiency on 15 d at 4 ℃,and the activity of paraoxonase was maintained basically stable.Conclusion The preparation of PEG-modified paraoxonase liposomes was easy and practicable,and the property investigation in vitro showed that the paraoxonase liposomes were stable.

The Preparation and the Anti-Tumor Targeting Therapy of Adriamycin Long Circulating Temperature-Sensitive Liposome / 中国肿瘤生物治疗杂志

Objective: To develop adriamycin liposome (AL) , adriamycin long circulating liposome (ALCL) and adriamycin long circulating temprerature-sensitive liposome ( ALTSL) and to study their anti-tumor effects on tumor-bearing mice. Methods: The antitumor activity was observed using the tumor weight as index. The life prolongation rate of mice was calculated according to the tumor-bearing mice survival time. The tissue distribution of adriamycin was determined by HPLC method. Tumor, heart, liver and kidney tissue of the tumor-bearing mice, were sliced and prepared to observe the tissue pathology differences. Results: Compared with free adriamycin, the anti-tumor effects of ALCL and ALTSL were remarkably increased. Their tumor growth inhibitory rates were 57. 8% and 67. 0% respectively. The study of pharmacoki-netics indicated that the adriamycin concentrations were remarkably higher in tumor tissue and blood,lower in heart and lung tissue of ALCL and ALTSL groups when compared with the free ADM group; The pathology slices indicated that tumor cells in the ALTSL group with hyperthermia were mostly destroyed; the cardiac muscle cells in the ALTSL group were similar to the normal cardiac muscle. Conclusion: ALCL and ALTSL remarkably increased the adriamycin concentration on the tumor site, significantly enhanced the anti-tumor effects, decreased the side-effects (such as cytotoxicity) when compared with free ADM, they also significantly prolonged the survival time of the tumor-bearing mice.